Conventionally, in the standardization organization 3GPP (3rd Generation Partnership Project), studies have proceeded on Evolved Universal Terrestrial Radio Access (hereinafter, referred to as “EUTRA”) evolved from the 3rd-generation mobile communication system, and Advanced EUTRA (also referred to as “LTE-Advance”) that is the further advanced form (Non-patent Document 1).
In Advanced EUTRA, Carrier Aggregation is proposed as techniques for enabling higher data transmission while maintaining compatibility with EUTRA (for example, Non-patent Document 2). Carrier Aggregation is techniques for preparing a reception apparatus having a reception bandwidth exceeding transmission bandwidths of transmission apparatuses, concurrently transmitting data from a plurality of transmission apparatuses configure for mutually different frequency bands, receiving in the reception apparatus the data concurrently transmitted from the plurality of transmission apparatuses, and thereby improving the data rate. In addition, hereinafter, the reception apparatus is described as a mobile station apparatus, and the transmission apparatus is described as a base station apparatus, but it is not necessary to limit the application scope of the invention to these apparatuses.
Then, in order to perform Carrier Aggregation effectively, it is necessary not to configure a frequency band of poor quality as a reception band. For this reason, the mobile station apparatus needs to perform Inter-Frequency Measurement. As a conventional method of Inter-Frequency Measurement, EUTRA adopts a method in which the base station apparatus configures a measurement gap during which transmission and reception is not performed (Non-patent Document 3). Meanwhile, for example, Patent Document 1 discloses a method in which the frequency band is divided into a main band and an expansion band, any measurement gap is not configure, the main band and a plurality of expansion bands are concurrently received, and an increase/decrease in the expansion band is determined based on the obtained quality information.    Patent Document 1: International Publication No. WO2006-046307    Non-patent Document 1: 3GPP TR36.913, Requirements for Further Advancements for E-UTRA.V8.0.0 http://www.3gpp.org/ftp/Spec/html-info/36913.htm    Non-patent Document 2: Ericsson, R1-082468, 3GPP TSG-RAN1 Meeting #53bis, Warsaw, Poland, Jun. 30-Jul. 4, 2008    Non-patent Document 3: 3GPP TS36.331, Radio Resource Control (RRC); Protocol specification, V8.2.0 http://www.3gpp.org/ftp/Spec/html-info/36331.htm